In mathematics, especially in set theory, a setA is a subset of a set B, or equivalently B is a superset of A, if A is "contained" inside B, that is, all elements of A are also elements of B. A and B may coincide. The relationship of one set being a subset of another is called inclusion or sometimes containment.
The slash ( /), also known as a stroke and by the technical term solidus, is a sign used as a punctuation mark and for various other purposes. It is often called a forward slash, a retronym used to distinguish it from the backslash ( \). It has many other names.
